Mill for grinding and reducing grain



J. STEVENS.

MILL FOR GRINDING AND REDUCING GRAIN, 550.

N0. 252,705. I Patented Ja11.24,1882.

NTTED STATES JOHN STEVENS, OF N PATENT 'EFTQE.

EENA II, WISUONS I N.

SPECIFICATION forming part of Letters Patent No. 252,705, dated January24, 1882.

Application filed December 16, 1879.

To all whom it may concern Be it known that I, JOHN S'rEvENs,of Neenah,in the county of Winnebago and State of Wisconsin, have inventedcertainnew and use ful Improvements in Mills for Grinding and Reducing Grainand other llIaterials, of ,which the following is a specification.

My invention relates particularly to that classof grinding-mills knownas roller-mills, in which two or more rolls work against each other andcrush or grind the material between them and it consists in an improveddress to be given to the rolls.

In the drawings, Figure 1 is a plan view of a machine embodying myinvention, the dress being shown as applied spirally. Fig. 2 is asection on the line 00 00 of Fig. 1. Figs. 3 and 4 represent modifiedforms of the dress.

A is a frame for the support of the operative parts of the machine. Inbearing-blocks (t a upon this frame arejournaled the rolls B The rollBis driven by means of a sheave or pinion upon its shaft I), connectedwith any suitable prime motor, and is geared with and drives the roll Bin such manner that the two revolve in opposite directionspr toward eachother.

The blocksa, in which the roll Bismounted, are secured to the frame bymeans of bolts or screws which pass through elongated slots in saidblocks to permit their horizontal adjustment. These blocks mighthowever, be connected to the frame by means of a tongue and groove toaccomplish the same object.

In lugs 1) upon the frame work are set adjusting-screws O, whichdetermine the maximum retreatof one roll from the other. Springs 0,acting in conjunction with these screws, enable such an adjustmentthatthe movable roll may yield elastically from the'other to a greater orless distance, and then be positively stopped from further retreating bythe screws C. Other screws, D,take into the blocks a upon the oppositeside from the first and bear against the blocks a, thereby by theiradjustment determining the minimum of distance between the two rolls.

The usual hopper andfeed-roll are intended to be placed above thegrinding-rolls, and it will be understood that a suitable meal-chest,conveyer, or other instrumentality will receive the ground or pulverizedmaterial beneath and flanks of the contiguous ribs as meeting in anangle, giving a surface of invected outline. In Fig. 3 the. groovesbetween the ribs are rounded, a cross-section thus presentingtheappearance of a continuing series of ogee curves. In Fi 4 there is adistinct and well-defined space between the flanks or bases ofcontiguous ribs, each rib thus standing by itself, but not so farremoved from the rest as to tail of croperation.

Various other modifications in the shape of the grooves will suggestthemselves, the salient feature of my invention being that the ribsshall be rounded-that is to say, made with an outline that presents tothe dress of'the opposing roll onlya series of blunt non-cutting crests.

The dress in Figs. 1 and 3 is shown asspiral, being giveuabouta quarterturn (more or less) in the length of the cylinder. In Fig. 4 it isstraight, the ribs running longitudinally of the cylinder. When appliedspirally it will run in the same direction upon both rolls, in orderthat, as they revolve, the ribs upon one opposing surface may cross theribs upon the other. It is not intended, in illustrating the lay of thedress in these figures in connection with special forms which itassumes, to indicate that the particular lay or trend is the bestadapted for the special form shown therewith, but only that the dress inall of its modifications may, when laid, assume or range between any ofthe lines indicated.

The character of the work to be done and the nature of the materialoperated upon will influence the degree of fineness to be given thedress. Rough work will necessitate a coarser dress than fine work. Insome cases, therefore, the dress may be extremely tine, in othersmeasurably coarse.

It may sometimes be found desirable to have the rolls move at the sameperipheral speed, and this, though not so generally advantageous, Iconsider within the principle of my invention.

I do not herein claim specifically anything made the subject of claimsin the application filed by me on the 13th day of February, 1878,

of which this present application is a division, and upon which LettersPatent No. 228,001 have been granted to me subsequent to the filinghereot'to wit, upon the 25th day of May, 1880 but 7 I \Vhat I do claim,and desire to secure by Letters Paten is- 1. A dress for the rolls ofroller-mills, composed of a series of parallel ribs having bluntnon-cutting crests and trending lengthwise of 30 the rol.

-2. In agrimling-mill,tl1.e eombinationot' two rolls driven at ditferentperipheral speeds, and haying a dress composed of a series of parallelribs trending lengthwise of the roll and formed with blunt non-cuttingcrests.

JOHN STEVENS. Witnesses:

Jos. G. PARKINSON, S. P. HoLLINesWoR'rn.

